Brake light switch



0, 1966 J. EDELBLUT BRAKE LIGHT SWITCH Filed Nov. 1963 lNVENTO/P JOHANNEDELBLUT ATTORNEYS United States Patent 3,270,317 BRAKE LIGHT SWITCHJohann Edelblut, Frankfurt am Main, Seckbach, Germany, assiguor toAlfred Fetz, Detroit, Mich. Filed Nov. 6, 1963, Ser. No. 321,973 8Claims. (Cl. 340-71) This invention relates to a brake light switch andmore particularly to a switch mechanism for automatically actuating asignal light on a motor vehicle when the motor vehicle comes to a stop.

The conventional stop light arrangement on a motor vehicle is designedsuch that the stop light is actuated when the brakes are applied but thestop light is extinguished when the brakes are released. Thus, if amotor vehicle comes to a complete stop on the highway and afterstopping, the brakes are released, the stop light will be extinguishedand there will be no warning to a following vehicle that the vehicleahead has come to a complete stop.

The object of the present invention is to provide a novel switchmechanism which is responsive to the speed of the vehicle for energizinga signal light whenever the vehicle comes to a complete stop or, ifdesired, when the speed of the vehicle is diminished to a predeterminedlow value.

In the drawing:

FIG. 1 is a sectional view of the switch mechanism of the presentinvention taken along the lines II of FIG. 2.

FIG. 2 is a sectional view of the switch mechanism taken along the lineII-II in FIG. 1.

FIGS. 3 and 4 are views showing alternate constructions for the switchcontact members.

The switch mechanism of the present invention includes a housing 1 inwhich is journalled a rotor 2 by means of a shaft 3. In the embodimentillustrated in FIGS. 1 and 2, the rotor 2 is designed to be rotated inthe direction of the arrow designated 4 by means of a cable or the like,not illustrated, connected to the projecting end of shaft 3. The drivingcable would be connected to the drive shaft or other part of the vehicleI so that the speed of rotor 2 would be proportional to the speed of thevehicle. Housing 1 contains sufficient liquid such as oil therein tocompletely submerge the rotor. The housing is adapted to be filled withoil by means of a filler plug 6 in the top wall 7 of the housing.

The housing itself comprises a body portion 11 with a cover plate 8secured to one side thereof and sealed in fluid tight relation by screws10. Housing 1 is formed of an electrical insulating material such asBakelite or the like. At one side of the housing, there is mountedwithin the housing a leaf spring member 13 which is secured to thehousing by means of a screw 14 passing through a bushing 12 in the wallof the housing. Nuts 15 on the outer end of screw 14 secure the screwand at the same time provide a terminal for a wire conductor 16extending from a signal light 17. A manual switch 18 is in seriescircuit with signal light 17 and battery 19. The battery is grounded asat 20. The housing 1 also includes a second electrical terminal in theform of a screw 24 connected to ground 20 by a conductor 25. Screw 24 isthreaded into an electrical conducting fitting 22 which is in turnthreaded into the boss 9 of cover plate 8 in which the shaft 3 isjournalled. Electrical connection between shaft 3 and fitting 22 isprovided by means of a contact 21 which is biased against the inner endof shaft 3 by an electrical conducting spring 23.

The circuit between terminals 15 and 24 is adapted to be closed by aswitch arm 26 mounted at the free end of leaf spring 13 and an arcuateshoe 27 which is fixedly supported at the free end of spring arm 26.Spring 13, arm 26 and shoe 27 are all formed of electrical conductingmaterials. Shoe 27 is of arcuate shape and forms a segment of an arehaving a diameter slightly greater than the diameter of rotor 2. Spring13 and arm 26 supports shoe 27 so that the shoe normally contacts theouter periphery of rotor 2 only at the limited portion designated 29.The remainder of shoe 27 is spaced slightly from the peripheral surfaceof rotor 2 so as to provide a tapered slot 28 between shoe 27 and theperiphery of rotor 2. The leading end of shoe 27 is bevelled inwardly asindicated at 30 and the trailing end of shoe 27 is outwardly bevelled asindicated at 31.

In the operation of the switch mechanism illustrated in FIGS. 1 and 2,when the vehicle is at rest and the switch 18, which may be the ignitionswitch of the vehicle, is turned to the on position, a circuit iscompleted from battery 19 through switch 18 and through signal light 17to the terminal 15 on the housing. The circuit continues through screw14, spring 13, arm 26 and shoe 27 to the rotor 2. The circuit iscompleted to ground through the shaft 3, contact 21, spring 23, fitting22, terminal 24 and conductor 25. Now, when the vehicle is travelling,shaft 3 rotates in the direction of the arrow designated 4 and at aspeed proportional to the speed of the vehicle, As the rotor 2 rotatesin the clockwise direction illustrated in FIG. 1, there is a tendencyfor fluid to be drawn into the tapered slot 28 and, depending upon theviscosity of the oil 5 and the speed of rotation of the rotor, a lightfilm of oil will be drawn between the inner surface of shoe 27 and theouter surface of rotor 2 of sufiicient thickness to open the circuit at27, 29. Thus, when the vehicle is travelling above a predetermined lowspeed, the signal light 17 will be extinguished but when the vehiclecomes to a stop or the speed thereof is diminished below a predeterminedvalue depending upon the adjustment of spring 13, signal light 17 willbe illuminated and will serve as a warning to the cars following thatthe vehicle ahead is either travelling very slowly or has come to acomplete stop. A slot 32 permits adjustment of spring 13.

It will be observed that with the arrangement illustrated in FIGS. 1 and2, if the vehicle is travelling in reverse, shaft 3 will rotate in acounterclockwise direction and the bevelled edge 31 on the trailing endof the shoe will prevent the oil in housing 1 from building up betweenshoe 27 and the periphery of the rotor 2. Thus, the signal light 17 willremain illuminated when the vehicle is travelling in reverse.

In the arrangement shown in FIG. 3, the switch arm 26a supports a shoe27a. Unlike the shoe 27 illustrated in FIGS. 1 and 2, the shoe 2711 hasa radially inwardly extending arcuate bump 29a at the center thereofwhich provides localized contact between the peripheral surface of rotor2 and shoe 27a. The opposite ends of shoe 27a are bevelled inwardly asindicated at 30a and 301). Since shoe 27a has "a diameter slightlygreater than the diameter of rotor 2, tapered inlet slots 34 and 35 areprovided on opposite sides of bump 29a between the outer surface of therotor and the inner surface of shoe 27a. With this arrangement, it willbe observed that if the vehicle is driven in reverse at a speed above apredetermined low value, the signal light 17 will be extinguished.

The arrangement shown in FIG. 4 is somewhat similar to that illustratedin FIGS. 1 and 2 with the exception, however, that two shoes 27b and 270are provided. These two shoes are supported by switch arms 26b and 26c,respectively. The two shoes 27b and 27c are disposed on opposite sidesof rotor 2 and arranged such that when the rotor is turning in thedirection of the arrow 4, shoe 27!; moves out of contact with rotor 2and when the rotor is turning in the opposite direction, that is, in thedirect-ion designated by arrow 33, shoe 27c is caused to move out ofcontact with rotor 2. In this arrangement, two lights may be operated bythe respective switch arms.

I claim:

1. A brake light switch for a motor vehicle comprising a liquid filledhousing, a rotor journalled in said housing, means for driving the rotorin accordance with the speed of the vehicle, an arcuate contact shoebiased against the peripheral surface of the rotor, said contact shoehaving a diameter slightly greater than the diameter of the rotor sothat there is only localized contact between the shoe and the peripheralsurface of the rotor, the arcuate portion of the shoe out of contactwith the rotor forming with the periphery of the rotor an inlet slotextending to the contacting portions of the shoe and rotor, thearrangement being such that when the rotor is rotated above apredetermined speed, the liquid in the housing is forced into said inletslot to shift the shoe out of contact with the rotor, a light, a sourceof electric current and means forming a series circuit including saidlight, current source, rotor and shoe.

2. A brake light switch as called for in claim 1 including a leaf springmounted on said housing and supporting said shoe.

3. A brake light switch as called for in claim 2 Wherein the leaf springis mounted on the housing by a screw which forms an electrical terminalon the housing, said shoe and said spring being formed of electricalconducting materials and said housing being formed of an electricalinsulating material.

4. A brake light switch as called for in claim 1 wherein said housing isformed of an electrical insulating material and including an electricalconducting member in said housing contacting said rotor and forming aportion of said electrical circuit.

5. A brake light switch as called for in claim 1 wherein said shoe isfashioned with a curved radially inwardly extending projection on theinner surface thereof which is of relatively short circumferentialextent.

6. A brake light switch as called for in claim 1 wherein said shoe atthe end thereof out of contact with the rotor is formed with an inwardlyinclined bevel.

7. A brake light switch as called for in claim 1 including a secondcontact shoe similar to the first contact shoe and positioned on theopposite side of the rotor as the first contact shoe, said two contactshoes being arranged such that when the rotor is rotated in onedirection, one of said contact shoes is caused to move out of engagementwith the rotor and when the rotor is rotated in the opposite direction,the other contact shoe is caused to move out of engagement with therotor.

8. A device for use on a motor vehicle comprising a liquid filledhousing, a rotor journalled in said housing, means for driving the rotorin accordance with the speed of the vehicle, an arcuate contact shoebiased against the peripheral surface of the rotor, said contact shoehaving a diameter slightly greater than the diameter of the rotor sothat there is only localized contact between the shoe and the peripheralsurface of the rotor, the arcuate portion of the shoe out of contactwith the rotor forming with the periphery of the rotor an inlet slotextending to the contacting portions of the shoe and rotor, thearrangement being such that when the rotor is rotated above apredetermined speed, the liquid in the housing is forced into said inletslot to shift the shoe out of contact with the rotor, an electricallyactuated device, a source of electric current and means forming acircuit including said electrically actuated device, current source,rotor and shoe for operating said electrically actuated device inresponse to the making and breaking of contact between the shoe androtor.

References Cited by the Examiner UNITED STATES PATENTS 2,678,977 5/1954Thatcher 200 2,698,365 12/1954 Gaylord et al 340-263 X 2,751,453 6/1956Gaylord et al. 20080 2,754,386 7/1956 Gaylord ZOO-80 2,832,864 4/1958Rapp 340 71 X NEIL C. READ, Primary Examiner.

A. H. WARING, Assistant Examiner.

8. A DEVICE FOR USE ON A MOTOR VEHICLE COMPRISING A LIQUID FILLEDHOUSING, A ROTOR JOURNALLED IN SAID HOUSING, MEANS FOR DRIVING THE ROTORIN ACCORDANCE WITH THE SPEED OF THE VEHICLE, AN ARCUATE CONTACT SHOEBIASED AGAINST THE PERIPHERAL SURFACE OF THE ROTOR, SAID CONTACT SHOEHAVING A DIAMETER SLIGHTLY GREATER THAN THE DIAMETER OF THE ROTOR SOTHAT THERE IS ONLY LOCALIZED CONTACT BETWEEN THE SHOE AND THE PERIPHERALSURFACE OF THE ROTOR, THE ARCUATE PORTION OF THE SHOE OUT OF CONTACTWITH THE ROTOR FORMING WITH THE PERIPHERY OF THE ROTOR AN INLET SLOTEXTENDING TO THE CONTACTING PORTIONS OF THE SHOE AND ROTOR, THEARRANGEMENT BEING SUCH THAT THE ROTOR IS ROTATED ABOVE A PREDETERMINEDSPEED, THE LIQUID IN THE HOUSING IS FORCED INTO SAID INLET SLOT TO SHIFTTHE SHOE OUT OF CONTACT WITH THE ROTOR, AN ELECTRICALLY ACTUATED DEVICE,A SOURCE OF ELECTRIC CURRENT AND MEANS FORMING A CIRCUIT INCLUDING SAIDELECTRICALLY ACTUATED DEVICE, CURRENT SOURCE, ROTOR AND SHOE